WO2010132086A1 - Dispositif et procédé de prévention et d'élimination d'accumulation de givre dans un compresseur de moteur à réaction par vibration de la vanne de prélèvement d'air par poussées asymétriques - Google Patents

Dispositif et procédé de prévention et d'élimination d'accumulation de givre dans un compresseur de moteur à réaction par vibration de la vanne de prélèvement d'air par poussées asymétriques Download PDF

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Publication number
WO2010132086A1
WO2010132086A1 PCT/US2010/001219 US2010001219W WO2010132086A1 WO 2010132086 A1 WO2010132086 A1 WO 2010132086A1 US 2010001219 W US2010001219 W US 2010001219W WO 2010132086 A1 WO2010132086 A1 WO 2010132086A1
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WIPO (PCT)
Prior art keywords
icing
engine
ice
oscillation
gas turbine
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PCT/US2010/001219
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English (en)
Inventor
Fergus D. Smith
Fergus S. Smith
Original Assignee
Smith Fergus D
Smith Fergus S
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Application filed by Smith Fergus D, Smith Fergus S filed Critical Smith Fergus D
Publication of WO2010132086A1 publication Critical patent/WO2010132086A1/fr

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
    • F02C9/00—Controlling gas-turbine plants; Controlling fuel supply in air- breathing jet-propulsion plants
    • F02C9/48—Control of fuel supply conjointly with another control of the plant
    • F02C9/50—Control of fuel supply conjointly with another control of the plant with control of working fluid flow
    • F02C9/52—Control of fuel supply conjointly with another control of the plant with control of working fluid flow by bleeding or by-passing the working fluid
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
    • F01D25/00—Component parts, details, or accessories, not provided for in, or of interest apart from, other groups
    • F01D25/02—De-icing means for engines having icing phenomena
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
    • F02C7/00—Features, components parts, details or accessories, not provided for in, or of interest apart form groups F02C1/00 - F02C6/00; Air intakes for jet-propulsion plants
    • F02C7/04—Air intakes for gas-turbine plants or jet-propulsion plants
    • F02C7/045—Air intakes for gas-turbine plants or jet-propulsion plants having provisions for noise suppression
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D27/00—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids
    • F04D27/02—Surge control
    • F04D27/0292—Stop safety or alarm devices, e.g. stop-and-go control; Disposition of check-valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/70—Suction grids; Strainers; Dust separation; Cleaning
    • F04D29/701—Suction grids; Strainers; Dust separation; Cleaning especially adapted for elastic fluid pumps

Definitions

  • NA Reference to federally sponsored research or development NA Reference to joint research agreements: NA Reference to sequence listing: NA
  • the present invention relates generally to gas turbine jet engines, and, in particular, to turbofan jet engines, and, in greater particularity, to turbofan anti-icing systems.
  • a supercooled liquid droplet is a form of water that remains liquid well below the melting point of water, which is 0 0 C. This is due to the fact that water requires a nucleating agent to allow it to freeze at 0 0 C. Without a nucleating agent to serve as a seed crystal, water may reach temperatures well below 0 °C . The practical effect of this is that supercoooled water droplets may then suddenly freeze the moment that such an agent is made available, such as at the surface of an engine component.
  • Supercooled droplets typically require stable atmospheric conditions to maintain their liquid state. This is because a volatile atmospheric environment provides the mixing that allows nucleating agents to interact with the supercooled droplets. This type of interaction accelerates the formation of solid ice particles.
  • the stable conditions necessary for maintaining a preponderance of supercoooled liquid water droplets does not generally exist in turbulent thunderstorms and tropical depressions that are characteristic of frozen ice particle-based turbofan compressor core icing incidents.
  • FIG. 10 is a diagram of the flight envelope of various jet engine shutdown events that appear to be caused by glaciated and/or mixed phase ice particles, as opposed to supercooled water. It is notable how the majority of these events occur in temperature conditions that are approximately 0° - 20 °F above International Standard Atmosphere expected temperatures (ISA). This upward shift in temperature is a reflection of the unusual power of the local convective storm activity, within which these events are occurring. The intensity of this activity allows clouds to thrust ice particles to greater altitudes than would be considered normal, as in FIG. 9.[I]
  • Vapor pressure is the equilibrium pressure of a vapor in thermodynamic equilibrium with its condensed phase in a closed container. All liquids and solids have a tendency to evaporate into a gaseous form, and all gases have a tendency to condense back to their liquid or solid form.
  • the equilibrium vapour pressure is an indication of a liquid's evaporation rate. It relates to the tendency of particles to escape from the liquid (or a solid). A substance with a high vapour pressure at normal temperatures is often referred to as volatile.
  • the vapor pressure of any substance increases non-linearly with temperature according to the Clausius-Clapeyron relation.
  • the atmospheric pressure boiling point of a liquid (also known as the normal boiling point) is the temperature at which the vapor pressure equals the ambient atmospheric pressure. With any incremental increase in that temperature, the vapor pressure becomes sufficient to overcome atmospheric pressure and lift the liquid to form bubbles inside the bulk of the substance. Bubble formation deeper in the liquid requires a higher pressure, and therefore higher temperature, because the fluid pressure increases above the atmospheric pressure as the depth increases.
  • the vapor pressure of a single component in a mixture is called partial pressure.
  • partial pressure For example, air at sea level, saturated with humidity at 20 0 C has a partial vapor pressures [sic] of 24 mbar of water, and about 780 mbar of nitrogen, 210 mbar of oxygen and 9 mbar of argon.
  • Vapor pressure is the sum of all of the individual partial pressures within a given system, and can be described with the following equation:
  • V P 1 + P 2 + ... + P N
  • V Vapor Pressure
  • P the partial pressure for a given chemical
  • Ice at 0 0 C is completely coated in liquid water and has a partial pressure identical to liquid water at 0 0 C, 4.579 mm Hg. As ice becomes cooler than 0 0 C, the proportion of liquid water to ice on the surface goes down. At -63 °C, the partial pressure water at the surface of ice is only 0.0053 mm Hg. At 100 °C water has a partial pressure of about 780 mm Hg. This is equal to and competitive with the vapor pressure of ambient air. Thus water boils if heat is supplied at the bottom of the vessel because its partial pressure is equal to or greater than that of the atmosphere. It is essentially pushing back against the weight of the air, while the raised water tumbles back down due to imbalances in the convection of the system.
  • the total amount of water available is not only low to begin with, but the warm air in the engine increases the air's saturation capacity by increasing the surface water's partial pressure, while lowering the relative humidity of the air. While it is true that a turbofan compressor increases the pressure of air as it passes through, its compression will not be perfectly adiabatic. This is because the rotors of the compressor will themselves promote warming of the air flow from friction. This will occur in addition to any warming that is achieved by compression alone, as predicted by Charles' Law. This effect will be most forcefully expressed in an inefficient engine.
  • the temperature gradient reverses again with temperature falling as you go up in the ionosphere.
  • the tropopause boundary is higher in warm weather, thus its ceiling varies widely between about 60,000' at the equator and about 30,000' at the Earth's poles. In the Northern United States it can vary from 30,000' to 50,000', depending on the temperature. This explains why engine powerloss events are occurring at higher than International Standard Atmospheric temperatures.
  • IMC instrument meteorological conditions
  • an ice particle starting at -40 °C for example, that adheres to an engine component surface after becoming liquefied to the melting point of water, 0 °C, will experience substantial evaporation, as well as sublimation, once the particle has stopped moving along with the airflow.
  • Low local humidity at the surface of the water and/or ice particle would be maintained in such a state by the constant airflow, which would prevent a local partial pressure equilibrium from developing at the surface of the particle.
  • the latent heat of vaporization serves as a basis for a considerable potential energy differential between a water droplet and the surface that it adheres to.
  • this liquefied and/or solid ice particle evaporates or sublimates, the subsequent thermal loss extracted from the engine component by evaporation and/or sublimation will be greater than the thermal input initially necessary to melt the ice.
  • the net thermal transfer as a whole will be mass efficient and highly negative for any ice or water particle that adheres to the surface.
  • latent heat because the temperature of water does not change while it is releasing or absorbing heat during its phase change.
  • Phase change refers to when a substance changes its composition between solid, liquid, or gaseous states.
  • latent heat is not designated as per "C the way that specific heat is.
  • a similar process occurs when 1 gram of water is vaporized, but the caloric transfer is about 600 c/g, or about 7.5 times greater than the latent heat of fusion.
  • the thermal conductivity for a material declines when it enters its gaseous phase. With less contact between molecules, less thermal transfer occurs. So air's thermal conductivity at 0 0 C is only about 0.024 W/mC (also expressed as (W * m) /( m 2 * 0 0 C)). Moreover, since air is a gas, thus low density, its specific heat, as expressed by volume, would be very low. The density of air at 1 atmosphere is only about 1.3 kg/m 3 at 0 0 C, dropping even further with increases in altitude. With lower density there are fewer molecules to serve as a heat source.
  • the inventors have hypothesized that ballistic effects are promoting the process of evaporation and/or sublimation. Because water is a polar molecule, water molecules are attracted to each other by virtue of the phenomenon known as hydrogen bonding. The result is that water prefers to aggregate into increasingly larger droplets because larger droplets cause less strain on the bonds between each molecule. While this effect can be readily observed during a rain storm on the front of a car windshield as small droplets coalesce into larger ones, this effect also occurs at the molecular level as well. The result is small puddles of water on a microscopic scale, and these puddles may be vaporized when oxygen and nitrogen molecules collide with these water puddles.
  • Page U of 58 ballistic vaporization can conceivably reduce the surface temperature of water by an additional 20 0 C to 30 ⁇ C or more, instead.
  • any melted water would be expelled from a component's surface as water droplets. This would be preferable to the water evaporating as a vapor.
  • ballistic effects and the existing partial pressure disequilibrium would cause the melted water to evaporate as soon as water puddles exist on the surface of the ice. Therefore, any melting that occurs from kinetic effects on the ice is overwhelmed by evaporative cooling. This effect is accentuated as the atmosphere's vapor pressure decreases with increasing altitude, reaching a maximum evaporation rate in a vacuum, such as outer space.
  • the conductive heat transfer caused by air directly to an ice or water particle is negligible because of the above factors, and the heat transfer by means of latent heat is dominant.
  • the relative humidity of air is below saturation when it rises, such as when it is pushed up the side of a mountain, it expands and cools at about 10 °C/1000m, or 10 °C/km. This is known as the dry adiabatic lapse rate, caused by the temperature decrease that occurs when a gas increases its volume.
  • the heat transfer would be at least 80 c/g + 600 c/g + 0.5 c/g 0 C * 40 ⁇ C, or 700 c/g, between the ice particle and a target surface. Of that 700 c/g, only 20 c/g, or 2.9% of that cooling would be due to the specific heat-related caloric transfer between of the ice particle and the warmer surface.
  • an ice particle on the surface of a stator or of the housing will have a lower surface temperature than the previous rotor. This creates a temperature gradient reversal, which is the necessary precondition for turbofan compressor core ice accretion. This is because the stator experiences a wet bulb temperature depression by virtue of the effects of evaporative cooling. Passing airflow maintains a constant humidity level at the surface of the water or ice particle, thus preventing the water from establishing local partial pressure equilibrium between its liquid (or solid) phase and its gaseous phase.
  • the wet bulb depression gradient will be at least between approximately 2 0 C and 10 °C at the surface of any water adhering to an engine component, and the previously known maximum depression of at least 10 °C, or possibly much higher from ballisticall ⁇ induced vaporization, will occur locally at the greatest concentration of adherent water and/or accreted ice.
  • the density of adherent water and/or accreted ice will directly correspond to the wet bulb temperature depression that is achieved.
  • an engine component that is 50% covered with ice will achieve a wet bulb depression of 50% of its maximum possible value.
  • a greater concentration of ice and/or water there will be greater local evaporative cooling, and thus a maximum wet bulb depression in that local area.
  • This wet bulb depression which can be created by water without the benefit of ice, is why a constantly increasing ambient temperature gradient can be maintained by an engine, while nonetheless creating a temperature gradient reversal at the surface of the ice or water. This reversal is what allows ice accretion to happen.
  • a functional but nonetheless unsteady state can be achieved by dynamically oscillating the temperature, pressure, and/or airflow gradients within the engine and in concert with the plane's other engines. This will be more effective than permanently shifting the engine to a stable higher or lower temperature state.
  • the compressor components such as but not limited to the stators/guide vanes and the rotors, will slightly alter their shape. This change in shape will cause ice to crack and to shed at subcritical levels because ice is an inelastic substance. Like shifting a balance beam under a gymnast, altering the throttle in anticipation of engine icing will allow the compressor component to destabilize the platform that is required for any accreted ice to maintain itself.
  • oscillating the temperature, pressure, and/or airflow gradient within the engine will allow the compressor rotors to serve as an additional means to disrupt the accretion of ice within the engine, while suppressing their contribution to the process by placing cooler air over the rotors and thereby limiting their ability to melt the ice particles that serve to bond other ice particles together.
  • the present invention is directed at a new anti-icing device and method for preventing and eliminating gas turbine jet engine compressor core ice accretion.
  • the present invention further provides a novel device for oscillating the fuel flow, the bleed air valve to the bypass, the engine's load to the environmental control unit, the load from the electricity generation system, or any variable geometry, in such a manner that the engine's steady state can be altered.
  • the present invention further provides control routines (150, 160, 170, 180) that may be used to alter the programming and/or the behavior of a plurality of engine control units (383), as well as a plurality of subroutines (161, 171, 181, 191) that are dependent upon the control routine's (150, 160, 170, 180) operation.
  • These control routines (150, 160, 170, 180) may be added into or adjoined to an engine control unit (383), and may be used to include the necessary mathematical equations and/or software programming to govern the anti-icing oscillation system (110, 120, 130, 140, 382). This will require modifications to existing engine control systems, including but not limited to engine control units (383), autothrottle systems, and/or autopilot systems.
  • the present invention further provides a novel device for adding precision to the anti-icing oscillation system.
  • Subroutines are directed to control each engine in parallel to and in concert with the others, as shown in FIG. 15, such that the total thrust of all engines operating together is maintained constant, despite thrust oscillations by each individual engine.
  • the present invention further provides a novel device to create for a uniform oscillation amplitude and frequency, or the oscillation be quantized such that the oscillation amplitude and/or frequency itself can be dithered randomly or deliberately, thus adding robustness to the anti-icing system.
  • the present invention further provides that a predetermined temperature indicating the zone possessing the greatest wet bulb depression may be used as a basis to anticipate locations of compressor core ice accretion.
  • the present invention further provides that by taking the absolute value of the difference between the high pressure compressor outlet temperature (HPCOT) and the low pressure compressor inlet temperature (LPCIT), or any two other temperature estimates from different locations within the compressor, the absolute value of the difference between the dry bulb equivalent to the wet bulb temperature at the zone within the compressor possessing the greatest capacity for core ice accretion (DBWBT) and the low pressure compressor inlet temperature (LPCIT), and creating a ratio of the latter divided by the former, the relative location of the freezing zone within the compressor can be calculated precisely.
  • This ratio can be expressed with the following formula:
  • the present invention further provides that by multiplying the above ratio, or another analogous formula, by the physical distance between the temperature input locations, the actual physical location of the freezing location can be inferred.
  • the present invention further provides that zone of greatest ice accretion in the compressor, or the equivalent dry bulb temperature that exists in the same region of the engine, can be determined by referring to a database of empirically derived engine temperature and pressure relationships.
  • the present invention further provides that the zone most favorable for stator and/or guide vane ice accretion can be deliberately forbidden or dynamically shifted to the compressor rotor blades, 24A-D and 28A-H. This can be achieved by altering the compressor operation settings, including but not limited to adjusting the fuel flow, adjusting the bleed valve to the bypass, adjusting the environmental control load, adjusting the electricity generation load, or adjusting any variable geometry inside or outside of the engine.
  • the present invention further provides throttle and/or bleed air valve settings that result in zone of greatest compressor core ice accretion is made to skip over the stators and/or guide vanes, so as to avoid icing of the stators, 23A-E and 27A-H, or any other stationary engine components as well.
  • the present invention further provides a basis for the use of forbidden throttle settings. This discourages ice accumulation by monitoring temperature gradients favorable to icing, and then deliberately avoiding them by manipulating the temperature gradients indirectly with the throttle, the bleed air valves, and or other means, such as but not limited to the environmental control unit (ECU).
  • ECU environmental control unit
  • the present invention further provides that if the icing accretion zone cannot be directly estimated, alternating the anti-icing system's oscillation amplitude and frequency, based on a predetermined engine temperature gradient, can ensure that the most favorable icing accretion zone will exist on the compressor's rotors with at least equal probability to that of the stators.
  • the present invention further provides a novel basis for adding robustness to the engine system by dithering of the steady state thrust levels of the engines asymmetrically in relation to each other. This means that each engine has a unique thrust demand placed upon it.
  • the present invention further provides a novel electrically powered control system for analog dithering of a gas turbine jet engine throttle.
  • This system utilizes an electrical oscillator HlA placed in line between the throttle IIOA and the engine system's fuel governor 112A.
  • the preferred embodiment for the electrical oscillator HlA is an electronic timing circuit, such as a "one shot" circuit or an electronic timer.
  • a switch 117 A normally closed when the anti-icing oscillation system is not in operation, is used to control when the oscillator HlA is in operation.
  • the fuel governor oscillator HlA can oscillate the thrust of the engine, thus oscillating the temperature and the pressure gradient within the compressor core.
  • the present invention further provides a novel hydraulically powered control system for mechanical dithering of a gas turbine jet engine throttle.
  • This system utilizes a hydraulic oscillator 13 IA placed in line between the throttle 130A and the engine system's fuel governor 132A.
  • the preferred embodiment for the hydraulic oscillator 131A is a rotating hydraulic pump, such that the movement of the pump controls a valve which in turn controls the fuel governor.
  • the present invention further provides a novel throttle-based anti-icing oscillation system. This system oscillates the throttle for (and fuel flow to) a plurality engines in concert with each other such that total thrust remains constant, while nonetheless eliminating compressor core ice accretion.
  • the present invention further provides a novel basis for an anti-icing oscillation system by oscillating the environmental control load on a plurality of engines. Once the environmental control load oscillation schedule is calculated 172, subroutines 173A, 173B, 174A, and 174B designated to each of one of the four engines are called to manipulate the environmental control load placed on each of these engines in concert with the other engines.
  • the present invention further provides for the inclusion of an environmental control unit (ECU) on all of an aircraft's engines. This is necessary because not all engines possess an environmental control unit.
  • ECU environmental control unit
  • the present invention further provides a novel basis for creating an anti-icing oscillation system by oscillating the throttle on a plurality engines in unison with each other, such that total thrust oscillates directly with the anti-icing system, while nonetheless eliminating compressor core ice accretion.
  • the present invention further provides a novel basis for creating an anti-icing oscillation system by oscillating the bleed valve to the bypass on a plurality engines, each in concert with the others such that total thrust remains constant. This is achieved by allowing the behavior of bleed air valves to operate in a manner that is out of phase with respect to the bleed air valves of the other engines.
  • the end result of the initialization process is an oscillation system that can manipulate the engine temperature gradient, while still maintaining constant thrust, by oscillating the settings to a plurality of bleed air valves.
  • the present invention further provides a novel basis for creating a hybrid anti-icing oscillation system by oscillating the bleed air valve to the bypass, in conjunction with oscillating the fuel flow, on a plurality engines, each in concert with the others such that total thrust remains constant.
  • the present invention further provides a novel basis for segmenting the throttle setting into two variables: a baseline throttle that is used in parallel by all engine systems, and an oscillating throttle, unique to each engine, that is controlled by the anti-icing oscillation system routines.
  • This system allows for increases or decreases in engine throttle to meet changing flight requirements, while maintaining the ability of thrust- altering anti-icing systems to perform their function.
  • throttle may be controlled by a variety of means that includes but is not limited to basing an engine's thrust off of the compressor's RPM and/or the pressure ratio of the compressor inlet pressure and the turbine exit pressure.
  • the baseline throttle can be adjusted such that the throttle of each engine is changed in unison, allowing the total thrust available to the plane to change in unison with it. If lower throttle is needed from all engines in equal amounts, the baseline throttle can be reduced, even as the oscillating throttle is operating independently of the baseline throttle. If greater throttle is needed from all engines in equal amounts, the baseline throttle can be increased, even as the oscillating throttle is operating independently of the baseline throttle.
  • the present invention is a turbofan jet engine compressor core anti- icing system.
  • An object of the present invention is to provide a basis to prevent and to eliminate ice accretion from within the compressor core of a turbofan jet engine.
  • FIG. 1 is a simplified schematic for the compressor stage of a prior art conventional gas turbine jet engine
  • FIG. 2 is a simplified schematic for the compressor stage of a prior art conventional gas turbine jet engine. [5] This provides additional detail to what was presented in FIG. 1;
  • FIG. 3 is a simplified schematic for the compressor stage of a prior art gas turbine jet engine. [5] This provides additional detail to what was presented in FIG. 2. However, instead of presenting engine parts, it describes areas of the engine that are prone to particular forms of icing;
  • FIG.4 is a representation of the airflow relationship between a prior art jet engine's rotors and its stators
  • FIG. 5 is a frontal view of a typical wide-body Boeing 747 jet airliner; [7] [131] FIG. 6 is an overhead view of a typical wide-body Boeing 747 jet airliner; [7]
  • FIG. 7 is a simplified schematic of a prior art air conditioning system for a jet airliner
  • FIG.8 is a simplified schematic of a novel air conditioning system for a jet airliner
  • FIG. 9 is an illustration of the airflow in a convective cloud storm system as it relates to the flight of a jet airliner through such a meteorological storm system;
  • FIG. 10 is a diagram of the flight envelope of various jet engine shutdown events that appear to be caused by glaciated and/or mixed phase ice particles, as opposed to supercooled water; [1,5,6]
  • FIG. 11 is a flow chart of a novel power control unit for a fuel governor for a gas turbine jet engine anti-icing system containing four jet engines;
  • FIG. 12 is a flow chart of a novel power control unit for a fuel governor for a gas turbine jet engine anti-icing system containing two jet engines;
  • FIG. 13 is a flow chart of a novel power control unit for a fuel governor for a gas turbine jet engine anti-icing system containing four jet engines;
  • FIG. 14 is a flow chart of a novel power control unit for a fuel governor for a gas turbine jet engine anti-icing system containing two jet engines;
  • FIG. 15 is a flow chart for a novel gas turbine jet engine throttle-based anti-icing system for a four engine aircraft. The purpose of this module is to alleviate icing conditions within the compressor section of the jet engine by oscillating and/or dithering of each engine's throttle settings;
  • FIG. 16 is a flow chart for a novel gas turbine jet engine throttle-based anti-icing system for a two engine aircraft.
  • the purpose of this module is to alleviate icing conditions within the compressor section of the jet engine by oscillating and/or dithering of each engine's throttle settings, while maintaining a constant direction by compensating with the plane's rudder;
  • FIG. 17 is a flow chart for a novel gas turbine jet engine environmental control unit based anti-icing system for a four engine aircraft possessing at least one environmental control pack connected to each of four individual engines.
  • the purpose of this module is to alleviate icing conditions within the compressor section of each jet engine by oscillating and/or dithering of each engine's environmental control load bleed air settings;
  • FIG. 18 is a flow chart for a novel gas turbine jet engine environmental control unit based anti-icing system for an aircraft possessing at least one environmental control pack connected to each of two individual engines. The purpose of this module is to alleviate icing conditions within the compressor section of each jet engine by oscillating and/or dithering of each engine's environmental control load bleed air settings;
  • FIG. 19 is a flow chart for a novel subroutine that is utilized by the anti-icing systems presented in FIG. 17 and FIG. 18;
  • FIG. 20 is a flow chart for a novel subroutine that is utilized by anti-icing systems presented in FIG. 17 and FIG. 18;
  • FIG. 21 is a flow chart for a novel gas turbine jet engine throttle-based anti-icing system for a four engine aircraft.
  • the purpose of this module is to alleviate icing conditions within the compressor section of the jet engine by oscillating each engine's total throttle settings in unison with the other, while maintaining constant elevation by adjusting the trim settings;
  • FIG. 22 is a flow chart for a novel gas turbine jet engine throttle-based anti-icing system for a two engine aircraft.
  • the purpose of this module is to alleviate icing conditions within the compressor section of the jet engine by oscillating each engine's total throttle settings in unison with the other, while maintaining constant elevation by adjusting the trim settings;
  • FIG. 23 is a flow chart for a novel subroutine that is utilized by the anti-icing systems presented in FIG. 21 and FIG. 22;
  • FIG. 24 is a flow chart for a novel subroutine that is utilized by the anti-icing systems presented in FIG. 21 and FIG. 22;
  • FIG. 25 is a flow chart for a novel gas turbine jet engine bleed air valve based anti- icing system for a four engine aircraft.
  • the purpose of this module is to alleviate icing conditions within the compressor section of the jet engine by oscillating and/or dithering of each engine's bleed air valve to the engine bypass settings;
  • FIG. 26 is a flow chart for a novel gas turbine jet engine bleed air valve based anti- icing system for a two engine aircraft.
  • the purpose of this module is to alleviate icing conditions within the compressor section of the jet engine by oscillating and/or dithering of each engine's bleed air valve to the engine bypass settings, while maintaining constant direction by adjusting the plane's rudder;
  • FIG. 27 is a flow chart for a novel subroutine that is utilized by the anti-icing systems presented in FIG. 25 and FIG.26;
  • FIG. 28 is a flow chart for a novel subroutine that is utilized by the anti-icing systems presented in FIG. 25 and FIG.26;
  • FIG. 29 is a flow chart for a novel subroutine that is utilized by the anti-icing systems presented in FIG. 25 and FIG. 26;
  • FIG. 30 is a flow chart for a novel subroutine that is utilized by the anti-icing systems presented in FIG. 25 and FIG. 26;
  • FIG. 31 is a flow chart for a novel subroutine that is utilized by the anti-icing systems presented in FIG. 25 and FIG.26;
  • FIG. 32 is a flow chart for a novel subroutine that is utilized by the anti-icing systems presented in FIG. 25 and FIG.26;
  • FIG. 33 is a flow chart for a novel gas turbine jet engine hybrid anti-icing system for a four engine aircraft.
  • the purpose of this module is to alleviate icing conditions within the compressor section of the jet engine by oscillating and/or dithering each engine's bleed air valve to the engine bypass settings, as well as each engines thrust, to create a hybrid anti- icing oscillation system;
  • FIG. 34 is a flow chart for a novel gas turbine jet engine hybrid anti-icing system for a four engine aircraft. The purpose of this module is to alleviate icing conditions within the compressor section of the jet engine by oscillating and/or dithering each engine's bleed air valve to the engine bypass settings, as well as each engines thrust, to create a hybrid anti- icing oscillation system, while maintaining constant direction by adjusting the plane's rudder;
  • FIG. 35 is a flow chart for a novel subroutine that is utilized by the anti-icing systems presented in FIG. 33 and FIG.34;
  • FIG. 36 is a flow chart for a novel subroutine that is utilized by the anti-icing systems presented in FIG. 33 and FIG. 34;
  • FIG. 37 is a diagram representing the temperature changes to the surface temperature of an exit guide vane during a test flight encounter with ice particle meteorological conditions. [1] This temperature time series is represented alongside the turbofan's low pressure compressor rotor speed, abbreviated as Nl; and
  • Fig. 38 is a flow chart depicting how a switch located in the cockpit, and therefore available to the pilot, may serve as a basis for the pilot to turn the anti-icing system.
  • the present invention is directed at a gas turbine jet engine compressor core anti- icing system.
  • FIG. 1 illustrates a spinner 10 according to the present invention.
  • FIG. 1 is a simplified schematic for the compressor stage of a conventional gas turbine jet engine.
  • the system is comprised of a spinner 10, a bypass fan 11, a plurality of core compressor stators 12, a plurality of rotors 13, a low pressure compressor stage 14A, a space 15 between the low and high compressors where bleed air valves are typically located, a high pressure compressor section 14B, the bypass 16A and 16B, and a high pressure compressor outlet 17.
  • Section 18 indicates the section of a gas turbine jet engine that has been determined by industry to be prone to supercooled water particle ice accretion.
  • Section 19 indicates the section of a gas turbine jet engine that has been determined by industry to be prone to glaciated and/or mixed phase water particle ice accretion.
  • FIG. 2 is a simplified schematic for the compressor stage of a conventional gas turbine jet engine. [5] This provides additional detail to what was presented in FIG. 1.
  • the system is comprised of a bypass fan 21; a bypass stator 22; a plurality of core low pressure compressor stators 23A, 23B, 23C, 23D, and 23E; a plurality of low pressure compressor rotors 24A, 24B, 24C, and 24D; a low pressure compressor bleed air duct 25A, low pressure compressor bleed air valve 26A, a plurality of core high pressure compressor stators 27A, 27B, 27C, 27D, 27E, 27F, 27G, and 27H; a plurality of highpressure compressor rotors 28A, 28B, 28C, 28D, 28E, 28F, 28G, and 28H; a low pressure compressor bleed air duct 25B; a low pressure compressor bleed air valve 26B; and a high pressure compressor outlet 29.
  • the arrow 20 indicates the flow direction of supercooled, glaci
  • FIG. 3 is a simplified schematic for the compressor stage of a conventional gas turbine jet engine. [5] This provides additional detail to what was presented in FIG. 2. However, instead of presenting engine parts, it describes areas of the engine that are prone to particular forms of icing.
  • the arrow in section 30 indicates the entry of supercooled, glaciated, and/or mixed phase water particles.
  • Section 31 indicates the jet engine section that industry has determined to be prone to supercooled liquid water droplet icing. This includes the inlet, the spinner, the bypass fan, the bypass stator, and the initial stages of the low pressure compressor 33, as described in FIG. 2.
  • Section 32 indicates the section of the engine that industry has determined to be prone to glaciated and/or mixed phase water particle icing. This includes the low pressure compressor 33, as well as the early stages of the high pressure compressor 34.
  • FIG. 4 is a representation of the airflow relationship between a conventional jet engine's rotors and its stators.
  • This representation is comprised of rotors 40, stators 41, arrows indicating the direction of inlet air flow 42, an arrow indicating the angular rotation 43 of the rotors 40 as they cut through the inlet air 42, arrows indicating the altered direction of the airflow 44 after it has been acted on by the rotors 40, and additional arrows indicate the corrected direction of the airflow 45 after its orientation has been restored by the stators 41. Take notice of the pointed direction of the stators 41 with respect to the airflow 44 from the rotors 40.
  • the prominence of the leading edge of jet engine stators 41 with respect to the incoming airflow 44 represents a narrow icing gathering point. This, in combination with a positive feedback loop from the engine control system, can create a runaway ice accretion point on the leading edge of the stators 41, despite the small size of the stators' 41 leading edge.
  • FIG. 5 is a frontal view of a typical wide-body Boeing 747 jet airliner.
  • This representation is comprised of a starboard outermost engine 50, a starboard innermost engine 51, a port innermost engine 52, a port outermost engine 53, an elevator 54, and a rudder 55.
  • the up arrows, 56A and 56B indicate how the trim and/or the elevator compensates for when the engine system's total net thrust decreases.
  • the down arrows, 57A and 57B indicate how the trim and/or direct control of the elevator compensates for when of the engine system's total net thrust increases.
  • the side arrows, 58A and 58B indicate how the rudder 55 compensates for the yaw that occurs when only two engines are oscillating their thrust.
  • the starboard engine or engines, 50 and/or 51 have more thrust than the port engine or engines, 52 and/or 53, this will cause the plane to yaw to the port side.
  • Positioning the rudder 55 to starboard will correct the yaw by directing the plane's tail to port 58A.
  • the port engine or engines, 52 and/or 53 have more thrust than the starboard engine or engines, 50 and/or 51, this will cause the plane to yaw to the starboard side.
  • Positioning the rudder 55 to port will correct the yaw by directing the plane's tail to starboard 58B.
  • FIG. 6 is an overhead view of a typical wide-body Boeing 747 jet airliner.
  • This representation is comprised of a starboard outermost engine 60, a starboard innermost engine 61, a port innermost engine 62, a port outermost engine 63, an elevator 64, a rudder 65, and ailerons and flaps 69A and 69B.
  • the side arrows, 68A and 68B, indicate how the rudder 65 compensates for the yaw that occurs when and if engine throttle oscillation causes one side of the jet to display more thrust than the other side. This state can occur when a plane oscillates only one engine on each wing, or when both engines on the wing oscillate in an identical manner.
  • FIG. 7 is a simplified schematic of a conventional air conditioning system for a jet airliner.
  • This system is comprised of two jet engines 7OA and 7OB, an isolation valve 71 to control the flow of air between the jet engine bleed air sources from each engine, valves 72A and 72B controlling the bleed air flow to the air conditioning packs 73A and 73B, recirculation fans 74A and 74B, a conduit for ground preconditioned air 75, a mix manifold 76, a trim air system 77 to adjust the air temperature for each individual region of the plane, and outlets to the flight deck 78A, the forward cabin 78B, and the aft cabin 78C.
  • FIG. 8 is a simplified schematic of an air conditioning system for a jet airliner.
  • This system is comprised of four jet engines 80A, 8OB, 8OC, and 8OD; isolation valves 81A, 81B, and 81C; to control the flow of air between the jet engine bleed air sources from each engine, valves 82A, 82B, 82C, and 82D controlling the bleed air flow to the air conditioning packs 83A, 83B, 83C, and 83D, recirculation fans 84A and 84B, a conduit for ground preconditioned air 85, a mix manifold 86, a trim air system 87 to adjust the air temperature for each individual region of the plane, and outlets to the flight deck 88A, the forward cabin 88B, and the aft cabin 88C.
  • FIG. 9 is an illustration of the airflow in a convective cloud storm system as it relates to the flight of a jet airliner through such a system.
  • This diagram shows how water particles are thrust high into the atmosphere, providing a means for their delivery into the inlet of a jet engine, even at cruising altitude.
  • FIG. 10 is a diagram of the flight envelope of various jet engine shutdown events that appear to be caused by glaciated and/or mixed phase ice particles, as opposed to supercooled water.
  • This diagram represents known icing envelopes Appendix C Continuous Maximum 100 and Appendix C Intermittent Maximum 101, linear regression lines representing International Standard Atmosphere expected temperatures (ISA) 102A, International Standard Atmosphere expected temperatures (ISA) plus 10° F 102B, and International Standard Atmosphere expected temperatures (ISA) plus 20° F 102C, and a plurality of engine flameout events 103 as they relate to International Standard Atmosphere temperatures.
  • ISA International Standard Atmosphere expected temperatures
  • ISA International Standard Atmosphere expected temperatures
  • ISA International Standard Atmosphere expected temperatures
  • ISA International Standard Atmosphere expected temperatures
  • ISA International Standard Atmosphere expected temperatures
  • ISA International Standard Atmosphere expected temperatures
  • 20° F 102C International Standard Atmosphere expected temperatures
  • FIG. 11 is a flow chart of a novel throttle control unit for a fuel governor for a gas turbine jet engine anti-icing system containing four jet engines.
  • This system is comprised of an anti-icing oscillation control system for each engine HOA, HOB, HOC, and HOD; throttles HlA HlB, HlC, and HID; fuel governor oscillators 112 A 112B, 112C, and 112D; fuel governors 113 A, 113 B, 113 C, and 113D; fuel pumps 114 A, 114B, 114C, and 114D to deliver the required fuel to the combustors 115A, 115B, 115C, and 115D at the core of each jet engine; sensors 116A, 116B, 116C, and 116D to provide engine information to the governors 113 A, 113B, 113C, and 113D about engine performance; and electrical communication 119A, 119B, 119C, and 119D to connect the system components together, including
  • the switches to the fuel governor oscillators 112A 112B, 112C, and 112D are normally open, and the switches 118 A, 118B, 118C, and 118D to the fuel governors 113 A, 113B, 113C, and 113D are normally closed.
  • the opposite switch arrangement by closing the switches 118 A, 118B, 118C, and 118D to the fuel governor oscillators 112 A 112B, 112C, and 112D, results when the anti-icing oscillation control system is in operation.
  • the fuel flow 117A, 117B, 117C, and 117D is represented by the bold, hashed arrows running through the fuel pumps 114 A, 114B, 114C, and 114D, and the combustors 115 A, 115B, 115C, and 115D.
  • the fuel governor oscillators 112A 112B, 112 C, and 112D can use a one shot electrical circuit or an electrical timer to control the oscillation process.
  • FIG. 12 is a flow chart of a novel power control unit for a fuel governor for a gas turbine jet engine anti-icing system containing two jet engines.
  • This system is comprised of an anti-icing oscillation control system 120A and 120B for each engine; throttles 12 IA and 12 IB; fuel governor oscillators 122A and 122B; fuel governors 123A and 123B; fuel pumps 124A and 124B to deliver the required fuel to the combustors 125A and 125B at the core of each jet engine; sensors 126A and 126B to provide engine information to the fuel governors 123A and 123B about engine performance; and electrical communication 129A and 129B to connect the system components together, including switches 128A and 128B to connect the fuel governor oscillators 122A and 122B to the fuel governors 123A and 123B.
  • This arrangement allows the option of selecting an oscillation mode for the fuel governors 123A and 123B, or running them normally without the interruption of the oscillators 122A and 122B.
  • the switches to the fuel governor oscillators 122A and 122B are normally open, and the switches to the fuel governors 123A and 123B are normally closed.
  • the opposite switch arrangement occurs when the anti-icing oscillation system is in operation.
  • the fuel flow 127A and 127B is represented by the bold, hashed arrows running through the fuel pumps 124A and 124B and the combustors, 125A and 125B.
  • the fuel governor oscillators 122A and 122B can use a one shot electrical circuit or an electrical timer to control the oscillation process.
  • FIG. 13 is a flow chart of a novel throttle control system for a gas turbine jet engine anti-icing system containing four jet engines.
  • This system is comprised of an anti-icing oscillation control system 130A, 130B, 130C, and 130D for each engine; throttles 131A, 131B, 131C, and 131D; fuel governor oscillators 132A 132B, 132C, and 132D; fuel governors 133A, 133B, 133C, and 133D; fuel pumps 134A, 134B, 134C, and 1340 to deliver the required fuel to the combustors 135A, 135B, 135C, and 135D at the core of each jet engine; sensors 136A, 136B, 136C, and 136D to provide information to the governors 133A, 133B, 133C, and 133D about engine performance; hydraulic valves, including but not limited to a ball valve or a solenoid valve, 138A, 138B, 138A
  • valve outlets to the fuel governor oscillators 132A, 132B, 132C, and 132D are normally closed, and the valve outlets to the fuel governors 133A, 133B, 133C, and 133D are normally open when the anti-icing oscillation system is OFF.
  • the opposite valve arrangement turns the anti-icing oscillation system is ON.
  • the fuel flow 137A, 137B, 137C, and 137D is represented by the bold, hashed arrows running through the fuel pumps 134A, 134B, 134C, and 134D, and the combustors 135A, 135B, 135C, and 135D.
  • the fuel governor oscillators 132A, 132B, 132C, and 132D can use a rotating hydraulic piston to serve as a basis for the oscillation. This can then be connected by linkage to a solenoid valve to control the fuel flow and/or the fuel governor behavior 133A, 133B, 133C, and 133D.
  • FIG. 14 is a flow chart of a novel throttle control system for a gas turbine jet engine anti-icing system containing two jet engines.
  • This system is comprised of an anti-icing oscillation control system 140A and 140B for each engine; throttles 141A and 141B; fuel governor oscillators 142A and 142B; fuel governors 143A and 143B; fuel pumps 144A and 144B, to deliver the required fuel to the combustors 145A and 145B at the core of each jet engine; sensors 146A and 146B to provide information to the governors 143A and 143B about engine performance; hydraulic valves, including but not limited to a ball valve or a solenoid valve, 148A and 148B to connect the fuel governor oscillators 142A and 142B to the fuel governors 143A and 143B, and hydraulic communication 149A and 149B to connect the system components together.
  • an anti-icing oscillation control system 140A and 140B for each engine
  • the valve outlets to the fuel governor oscillators 142A and 142B are normally closed, and the valve outlets to the fuel governors 143A and 143B are normally open when the anti-icing oscillation system is OFF.
  • the opposite valve arrangement turns the anti- icing oscillation system is ON.
  • the fuel flow 147A and 147B is represented by the bold, hashed arrows running through the fuel pumps 144A and 144B, and the combustors 145A and 145B.
  • the fuel governor oscillators 142A and 142B can use a rotating hydraulic piston to serve as a basis for the oscillation. This can then be connected by linkage to a solenoid valve to control the fuel flow and/or fuel governor behavior 143A and 143B.
  • FIG. 15 is a flow chart for a novel gas turbine jet engine throttle-based anti-icing system 110, 120, 130, 140 for a four engine aircraft.
  • the purpose of this system is to alleviate icing conditions within the compressor section of the jet engine by oscillating and/or dithering of each engine's throttle settings.
  • This system is comprised of an anti- icing control routine 150 that governs behavior of subroutines that are nested within the program; a power ON or OFF conditional 151 that determines whether the thrust oscillation anti-icing control routine 150 is set to ON. When the power is OFF or returns with a NO, then the routine reverts back to the anti-icing control routine 150 unchanged.
  • a thrust oscillation schedule routine 152 This routine determines the engine throttle oscillation schedule according to the compressor stage temperatures and/or pressure gradients for each of the jet aircraft's engines, in addition, call commands 153A and 153B are directed to an engine control subroutine, Thrust Oscillation Sub One", depicted in FIG. 23. Thrust Oscillation Sub One governs the thrust oscillation for any engine that the routine is dedicated to by the anti-icing control routine 150. Similarly, call commands 154A and 154B are directed to an engine control subroutine, Thrust Oscillation Sub Two", depicted in FIG. 24.
  • Thrust Oscillation Sub Two governs the thrust oscillation for any two engines that the routine is dedicated to by the antHcfng control routine 150.
  • Call commands 153A, 153B, 154A, and 154B all run in parallel to each other. As each subroutine operates and the thrust of each engine is oscillated up and down, the net total thrust produced by all engines is held constant.
  • the output of the anti-icing control routine 150 and the call commands 153A, 153B, 154A, and 154B are in communication with at least one engine control unit 159, which possesses control over at least one throttle 111, 121, 131, 141 to at least one engine 50, 60.
  • FIG. 16 is a flow chart for a novel gas turbine jet engine control unit throttle-based anti-icing system 110, 120, 130, 140 for a two engine aircraft.
  • the purpose of this system is to alleviate icing conditions from within the compressor section of the jet engine by oscillating and/or dithering of each engine's throttle settings, while maintaining a constant direction by compensating with the plane's rudder.
  • This system is comprised of an anti- icing control routine 160 that governs behavior of subroutines that are nested within the program; a power ON or OFF conditional 161 that determines whether the thrust oscillation anti-icing control routine 160 is set to ON.
  • a thrust oscillation schedule routine 162 This routine determines the engine throttle oscillation schedule according to the compressor stage temperatures and/or pressure gradients for each of the jet aircraft's engines.
  • a call command 163 is directed by the anti- icing control routine 160 to an engine control subroutine. Thrust Oscillation Sub One", depicted in FIG. 23. Thrust Oscillation Sub One governs the thrust oscillation for any two engines that the routine is dedicated to by the anti-icing control routine 160.
  • a call command 164 is directed by the anti-icing control routine 160 to an engine control subroutine.
  • Thrust Oscillation Sub Two 0 depicted in RG. 24.
  • Thrust Oscillation Sub Two governs the engine oscillation for any two engines that the routine is dedicated to by the anti-icing control routine 160.
  • a yaw adjust routine 165 corrects the plane's yaw by using the aircraft's autopilot.
  • the call commands 163 and 164, and the yaw control routine 165 all run in parallel to each other. As each subroutine operates and the thrust of each engine is oscillated up and down, the net total thrust produced by all engines is held constant, and the aircraft is able to maintain straight and level flight.
  • the output of the anti-icing control routine 160 and the call commands 163, 164 the yaw adjust routine 165 are in communication with at least one engine control unit 169, which possesses control over at least one throttle 111, 121, 131, 141 to at least one engine 50, 60.
  • FIG. 17 is a flow chart for a novel gas turbine jet engine environmental control unit- based anti-icing system 110, 120, 130, 140 for a four engine aircraft.
  • the purpose of this system is to alleviate icing conditions within the compressor section of the jet engine by oscillating and/or dithering of each engine's environmental control unit settings.
  • This system is comprised of an anti-icing control routine 170 that governs behavior of subroutines that are nested within the program; a power ON or OFF conditional 171 that determines whether the environmental control unit oscillation anti-icing routine 170 is set to ON. When the power is OFF or returns with a NO, then the routine reverts back to the anti-icing control routine 170 unchanged.
  • an environmental control unit oscillation schedule routine 172 This routine determines the environmental control units' oscillation schedule according to the compressor stage temperatures and/or pressure gradients for each of the jet aircraft's engines.
  • call commands 173A and 173B are directed to an engine control subroutine, Bleed to Air Control Sub One, depicted in FIG. 19. Bleed to Air Control Sub One is used to govern the environmental control unrf s oscillation for any engine that the routine is dedicated to by the anti-icing control routine 170.
  • call commands 174A and 174B are directed to an engine control subroutine. Bleed to Air Control Sub Two, depicted in FIG. 20.
  • Bleed to Air Control Sub Two is used to govern the environmental control unif s oscillation for two of the plane's four available engines.
  • Call commands 173A, 173B, 174A, and 174B all run in parallel to each other. As each subroutine operates and the total environmental control load placed upon each engine is oscillated up and down, while the net total thrust and the net total environmental control load placed upon all engines is held constant.
  • the output of the anti-icing control routine 170 and the call commands 173A, 173B, 174A, and 174B are in communication with at least one engine control unit 179, which possesses control over at least one throttle 111, 121, 131, 141 to at least one engine 50, 60.
  • FIG. 18 is a flow chart for a novel gas turbine jet engine environmental control unit- based anti-icing system 110, 120, 130, 140 for a four engine aircraft.
  • the purpose of this system is to alleviate icing conditions within the compressor section of the jet engine by oscillating and/or dithering of each engine's environmental control unit settings.
  • This system is comprised of an ant Nc ing control routine 180 that governs behavior of subroutines that are nested within the program; a power ON or OFF conditional 181 that determines whether the environmental control unit oscillation anti-icing control routine 180 is set to ON. When the power is OFF or returns with a NO, then the routine reverts back to the anti-icing control routine 180 unchanged.
  • an environmental control unit oscillation schedule routine 182 determines the environmental control units' oscillation schedule according to the compressor stage temperatures and/or pressure gradients for each of the jet aircraft's engines.
  • a call command 183 is directed to an engine control subroutine, Bleed to Air Control Sub One, depicted in FIG. 19. Bleed to Air Control Sub One is used to start the environmental control unrf s oscillation for any engine that the routine is dedicated to by the anti-icing control routine 180.
  • a call command 184 is directed to an engine control subroutine. Bleed to Air Control Sub Two, depicted in FIG. 20.
  • Bleed to Air Control Sub Two is used to start the environmental control unit's oscillation for two of the plane's four available engines.
  • the call commands 183 and 184, and a yaw control routine 185 all run in parallel to each other.
  • the yaw control routine 185 uses the aircraft's rudder and autopilot to maintain a straight course. Note that adjusting for yaw will only be necessary if constant fuel is maintained during the oscillation of the environmental control load. Altering the temperature gradient within the engine will still occur, even at constant thrust, once the bleed valve setting has been altered.
  • the output of the anti-icing control routine 180 and the call commands (183, 184) the yaw adjust routine 185 are in communication with at least one engine control unit 189, which possesses control over at least one throttle 111, 121, 131, 141 to at least one engine 50, 60.
  • FIG. 19 is a flow chart for a novel subroutine, referred to as "Bleed to Air Control Sub One", that is utilized by the anti-icing systems presented in FIG. 17 and FIG. 18.
  • This system is comprised of an initialization routine 190 that stores the engine's environmental control load settings at the outset of the routine, an environmental control unit (ECU) load routine 191 to gradually increase the environmental control load according to the compressor stage's temperature and/or pressure gradient, an ECU peak setting conditional 192 that determines whether the engine's environmental control load has increased to its peak setting, an ECU load decrease routine 193 to offset the engine's environmental load, an ECU trough setting conditional 194 that determines whether the engine's environmental load has been offset by twice the gain that resulted from the ECU load increase routine 191, an ECU load decrease routine 195 to restore the environmental load to its initial levels, an ECU restoration conditional 196 that determines whether the engine's initial environmental control load has returned to the same setting that was stored by the initialization subroutine
  • FIG. 20 is a flow chart for a novel subroutine, referred to as "Bleed to Air Control Sub Two", that is utilized by the anti-icing systems presented in FIG. 17 and FIG. 18.
  • This system is comprised of an initialization routine 200 that stores the engine's environmental control load settings at the outset of the initialization routine 200, an ECU load decrease routine 201 to gradually decrease the environmental control load according to the compressor stage's temperature and/or pressure gradient, an ECU trough setting conditional 202 that determines whether the engine's environmental control load has decreased to its trough setting, an ECU load increase routine 203 to increase the engine's environmental load, an ECU peak setting conditional 204 that determines whether the engine's environmental load has been increased by twice the decrease that resulted from the ECU load decrease routine 201, an ECU load decrease routine 205 to decrease the environmental load to its initial levels, an ECU restoration conditional 206 that determines whether the engine's initial environmental control load has returned to the same setting stored by the initialization subroutine 200,
  • FIG. 21 is a flow chart for a novel gas turbine jet engine throttle-based anti-icing system 110, 120, 130, 140 for a four engine aircraft.
  • the purpose of this system is to alleviate icing conditions within the compressor section of the jet engine by oscillating each engine's total throttle settings in unison with the other, while maintaining constant elevation by adjusting the trim settings.
  • This system is comprised of an anti-icing control routine 210 that governs behavior of subroutines that are nested within the program; a power ON or OFF conditional 211 that determines whether the throttle oscillation anti- icing control routine 210 is set to ON. When the power is OFF or returns with a NO, then the routine reverts back to the anti-icing control routine 210 unchanged.
  • a throttle increase routine 212A that increases the engine's throttle in anticipation of the anti-icing system's subroutines
  • a trim adjust routine 213A that runs in parallel with 212A and adjusts the plane's trim so as to maintain constant altitude
  • a throttle oscillation schedule routine 214 that determines the total throttle oscillation schedule according to each compressor stage's temperature and/or pressure gradient
  • four parallel call commands 215A, 215B, 215C and 215D to an engine control subroutine.
  • Throttle Oscillation Sub starts the routine by increasing each engine's throttle in unison with the other engines; a trim adjust routine 217 that, while running in parallel to commands 215A, 215B, 215C and 215D, adjusts the plane's trim to maintain constant altitude by using the autopilot; a power ON conditional 218 that determines whether the anti-icing system is still in operation; a throttle decrease routine 212B that decreases the engine's throttle to restore the throttle to levels prior to step 212A; and a trim adjust routine 213B that runs in parallel with 212B to adjust the plane's trim so as to maintain constant altitude.
  • At least one engine control unit 219 with control over at least one engine (50, 60) maintains communication with the anti-icing control routine 210, and the system's other routines (212, 213, 214, 215, 217) during the anti-icing system's (110, 120, 130, 140) operation. Note that adjusting the trim may not be necessary, in that adjusting the total thrust may simply oscillate the total velocity of the plane.
  • FIG. 22 is a flow chart for a novel gas turbine jet engine throttle-based anti-icing system 110, 120, 130, 140 for a two engine aircraft.
  • the purpose of this system is to alleviate icing conditions within the compressor section of the jet engine by oscillating each engine's throttle settings in unison with the other engine, while maintaining constant elevation by adjusting the trim settings.
  • This system is comprised of an anti-icing control routine 220 that governs behavior of subroutines that are nested within the program; a power ON or OFF conditional 221 that determines whether the throttle oscillation anti- icing control routine 220 is set to ON. When the power is OFF or returns with a NO, then the routine reverts back to the anti-icing control routine 220 unchanged.
  • the program proceeds to an throttle increase routine 222A that increases the engine's throttle in anticipation of the anti-icing system's other subroutines; a trim adjust routine 223A that runs in parallel with 222A and adjusts the plane's trim to maintain constant altitude; a throttle oscillation schedule routine 224 that determines the total throttle oscillation schedule according to each compressor stage's temperature and/or pressure gradient; a call command 225 to an engine control subroutine, Throttle Oscillation Sub One, depicted in FIG.
  • At least one engine control unit 229 with control over at least one engine 50, 60 maintains communication with the anti-icing control routine 220, and the system's other routines 222, 223, 224, 225, 226, 227 during the anti-icing system's 110, 120, 130, 140 operation. Note that adjusting the trim may not be necessary, in that adjusting the total thrust may simply oscillate the total velocity of the plane.
  • FIG. 23 is a flow chart for a novel subroutine, referred to as Throttle Oscillation Sub One, that is utilized by the anti-icing systems presented in FIG. 21 and FIG. 22.
  • This subroutine is comprised of an initialization routine 230 that stores the engine's operation settings at the outset of the initialization routine 230, a throttle increase routine 231 to gradually increase the throttle according to the compressor stage's temperature and/or pressure gradient, a throttle peak setting conditional 232 that determines whether the engine's throttle has increased to its peak setting, a throttle decrease routine 233 to offset the engine's throttle, a throttle trough setting conditional 234 that determines whether the engine's throttle has been offset by twice the gain that resulted from the throttle increase routine 231, a throttle increase routine 235 to increase the throttle, a throttle restoration conditional 236 that determines whether the engine's throttle has returned to the same setting as at the beginning of the initialization subroutine 230, and a return command 237 to return the program counter to the calling routine.
  • an initialization routine 230 that stores the engine's operation settings at the outset of the initialization routine 230
  • a throttle increase routine 231 to gradually increase the throttle according to the compressor stage's temperature and
  • FIG. 24 is a flow chart for a novel subroutine, referred to as Throttle Oscillation Sub Two, that is utilized by the engine control modules presented in FIG. 21 and FIG. 22.
  • This system is comprised of an initialization routine 240 that stores the engine's operating settings at the outset of the initialization routine 240, a throttle decrease routine 241 to gradually decrease the throttle according to the compressor stage's temperature and/or pressure gradient, a throttle trough setting conditional 242 that determines whether the engine's pressure ratio has decreased to its trough target setting, a throttle increase routine 243 to gradually restore and overshoot the lost throttle by increasing the throttle by twice the initial decreased amount, a throttle peak setting conditional 244 that determines whether the engine's throttle peak target has been reached, a throttle decrease routine 245 to decrease the throttle, a throttle restoration conditional 246 that determines whether the engine's throttle has returned to the same setting as at the beginning of the initialization subroutine 240, and a return command 247 to return the program
  • FIG. 25 is a flow chart for a novel gas turbine jet engine bleed air valve-based compressor core anti-icing system 110, 120, 130, 140 for a four engine aircraft.
  • the purpose of this system is to alleviate icing conditions within the compressor section of the jet engine by oscillating and/or dithering of each engine's bleed air valve settings to the compressor bypass.
  • This system is comprised of an anti-icing control routine 250 that governs behavior of subroutines that are nested within the system; a power ON or OFF conditional 251A that determines whether the bleed air valve oscillation anti-icing control routine 250 is set to ON. When the power is OFF or returns with a NO, then the routine reverts back to the anti-icing control routine 250 unchanged.
  • a bleed valve oscillation schedule subroutine 252A to calculate the bleed air oscillation schedule according to the each compressor's temperature and/or pressure gradient; parallel call commands 253A and 253B to Initialization Subroutine One, depicted in FIG. 29; parallel call commands 254A and 254B to Initialization Subroutine Two, depicted in FIG. 30; a bleed valve oscillation schedule subroutine 252B to recalculate the bleed air schedule; parallel call commands 255A and 255B to the Bleed to Bypass Sub One subroutine, depicted in FIG.
  • At least one engine control unit 259 with control over at least one engine (50, 60) maintains communication with the anti-icing control routine 250, and the system's other routines 252, 253, 254, 255, 257, 258 during the anti-icing system's 110, 120, 130, 140 operation. Altering the temperature gradient within the engine will still occur, even at constant throttle, once the bleed valve setting has been altered.
  • FIG. 26 is a flow chart for a novel gas turbine jet engine bleed air valve-based compressor core anti-icing system 110, 120, 130, 140 for a two engine aircraft.
  • the purpose of this system is to alleviate icing conditions within the compressor section of the jet engine by oscillating and/or dithering of each engine's bleed air valve to the engine bypass settings, while maintaining constant direction by adjusting the plane's rudder.
  • This system is comprised of an anti-icing control routine 260 that governs behavior of subroutines that are nested within the program; a power ON or OFF conditional 261A that determines whether the bleed air valve oscillation anti-icing control routine 260 is set to ON.
  • a bleed valve oscillation schedule subroutine 262A to calculate the bleed air oscillation schedule according to the each compressor's temperature and/or pressure gradients; a parallel call command 263A to the bleed air valve Initialization Subroutine One, depicted in FIG. 29; a parallel call command 263B to the bleed air valve Initialization Subroutine Two, depicted in FIG.
  • a yaw adjust routine 264A operating in parallel with the initialization routines 263A and 263B by adjusting the rudder by the autopilot; a bleed air valve oscillation schedule routine 262B to recalculate the bleed air schedule; a parallel call command 265A to the Bleed to Bypass Sub One subroutine, depicted in FIG. 27; a parallel call command 265B to the Bleed to Bypass Sub Two subroutine, depicted in FIG.
  • a yaw adjust routine 264B operating in parallel to the bleed the bypass routines 265A and 265B to adjust for yaw by adjusting the rudder by using the autopilot; a power ON conditional 261B that determines whether the bleed air anti-icing oscillation control routine is set to ON; a parallel call command 266A to the Restoration Subroutine One, depicted in FIG. 31; and a parallel call command 266B to the Restoration Subroutine Two, depicted in FIG. 32; and a yaw adjust routine 264C operating in parallel with the bleed air valve restoration routines 266A and 266B to adjust for yaw by adjusting the rudder by the autopilot.
  • At least one engine control unit 269 with control over at least one engine 50, 60 maintains communication with the anti-icing control routine 260, and the system's other routines 262, 263, 264, 265, 266 during the anti-icing system's 110, 120, 130, 140 operation.
  • FIG. 27 is a flow chart for a novel subroutine, referred to as "Bleed to Bypass Sub One", which is utilized by anti-icing systems presented in FIG. 25 and FIG. 26.
  • This subroutine is comprised of an initialization routine 270 that stores the engine's operation settings at the outset of the initialization subroutine 270, a bleed valve close routine 271 to gradually close the bleed valve to the bypass according to the compressor stage's temperature and/or pressure gradient, a bleed valve close conditional 272 that determines whether the compressor's temperature and/or pressure gradient has increased to its peak setting, a bleed valve open routine 273 to decrease the compressor's temperature and/or pressure gradient by opening the bleed valve to the engine's bypass while maintaining constant fuel flow, a bleed valve open conditional 274 that determines whether the bleed valve to the bypass has opened to the initialization subroutine's 270 initial setting, and a return command 275 to return the program counter to the calling routine.
  • an initialization routine 270 that stores
  • Pressure ratio is defined here as the ratio of the inlet pressure of the low pressure compressor and the exit pressure of the high pressure compressor. This can be altered by maintaining constant fuel flow to the engine while simultaneously adjusting the bleed valve to the bypass. Conversely, the pressure ratio can also be maintained constant. This can be done by increasing or decreasing the fuel flow respectively in response to changing pressure conditions created by altering the bleed valve setting.
  • FIG. 28 is a flow chart for a novel subroutine, referred to as "Bleed to Bypass Sub Two", which is utilized by the anti-icing systems presented in FIG. 25 and FIG. 26.
  • This subroutine is comprised of an initialization routine 280 that stores the engine's operation settings at the outset of the initialization routine 280, a bleed valve open routine 281 to gradually open the bleed valve to the bypass according to the compressor stage's temperature and/or pressure gradient, a bleed valve open conditional 282 that determines whether the compressor stage's temperature and/or pressure gradient has decreased to its trough setting, a bleed valve close routine 283 to restore the compressor stage's temperature and/or pressure gradient by closing the bleed valve to the engine's bypass, a bleed valve close conditional 284 that determines whether the bleed valve to the bypass has closed to the initialization subroutine's 280 initial levels, and a return command 285 to return the program counter to the calling routine.
  • an initialization routine 280 that stores the engine
  • Pressure ratio is defined here as the ratio of the inlet pressure of the low pressure compressor and the exit pressure of the high pressure compressor. This can be altered by maintaining constant fuel flow to the engine while simultaneously adjusting the bleed valve to the bypass. Conversely, the pressure ratio can also be maintained constant. This can be done by increasing or decreasing the fuel flow respectively in response to changing pressure conditions created by altering the bleed valve setting.
  • FIG. 29 is a flow chart for a novel subroutine, referred to as "Bleed Air Valve Initialization Sub One", that is utilized by the anti-icing systems presented in FIG. 25 and FIG. 26.
  • This subroutine is comprised of an initialization routine 290 that stores the engine's operation settings at the outset of the initialization routine 290, a throttle increase routine 291 to gradually increase the engine throttle according the compressor stage's temperature and/or pressure gradient, a throttle peak setting conditional 292 to determine whether the engine's throttle has increased to its peak setting, a bleed valve open routine 293 to gradually offset the gained throttle by opening the bleed valve to the bypass, and a conditional 294 to determine whether opening the bleed valve has offset twice the initial throttle gain, and a return command 295 to return the program counter to the calling routine.
  • FIG. 27 and FIG. 28 for an explanation of the relationship between the bleed valve to the bypass setting, fuel flow, throttle, total thrust from an engine, and the alteration of the temperature within the compressor stage.
  • FIG. 30 is a flow chart for a novel subroutine, referred to as "Bleed Air Valve Initialization Sub Two", which is utilized by the anti-icing systems presented in FIG. 25 and FIG. 26.
  • This subroutine is comprised of an initialization routine 300 that stores the engine's operation settings at the outset of the initialization routine 300, a bleed valve open routine 301 to gradually reduce the compressor's pressure by gradually opening the bleed valve to the bypass according to the compressor stage's temperature and/or pressure gradient, a bleed air valve open conditional 302 to determine whether the bleed valve setting has decreased to its trough target setting, a bleed valve close routine 303 to gradually restore the lost compressor pressure by closing the bleed valve to the bypass, a bleed valve close conditional 304 to determine whether the closing the bleed valve has restored its original settings, a throttle increase routine 305 to gradually increase the throttle according to the compressor stage's temperature and/or pressure gradient, a throttle peak setting conditional 306 to determine if the throttle has increased to its peak setting
  • FIG. 31 is a flow chart for a novel subroutine, referred to as "Restoration Subroutine One", which is utilized by the anti-icing systems presented in FIG. 25 and FIG. 26.
  • This subroutine is comprised of an initialization routine 310 that stores the engine's operating settings at the outset of the initialization routine 310, a bleed valve close routine 311 to gradually increase the compressor pressure by gradually closing the bleed valve to the bypass, a bleed valve restoration conditional 312 to determine whether the bleed valve to the bypass has been restored to its pre-oscillation setting, a throttle decrease routine 313 to gradually decrease the engine throttle, a throttle restoration conditional 314 to determine whether the throttle has been restored to the engine's pre-oscillation throttle setting, and a return command 315 to return the program counter to the calling routine.
  • FIG. 27 and FIG. 28 for an explanation of the relationship between the bleed valve to the bypass setting, fuel flow, throttle, total thrust from an engine, and the alteration of the temperature within the compressor stage
  • FIG. 32 is a flow chart for a novel subroutine, referred to as "Restoration Subroutine Two", which is utilized by the anti-icing systems presented in FIG. 25 and FIG. 26.
  • This subroutine is comprised of an initialization routine 320 that stores the engine's operation settings at the outset of the initialization routine 320, a throttle decrease routine 321 to gradually lower the throttle, a throttle restoration conditional 322 to determine whether the throttle has decreased to its pre-oscillation setting, a bleed valve open routine 323 to gradually reduce the compressor pressure by opening the bleed valve to the bypass, a bleed valve open conditional 324 to determine whether opening the bleed valve has reduced the compressor's pressure to its target trough setting, a bleed valve close routine 325 to gradually close the bleed valve to the bypass, a bleed valve restoration conditional 326 to determine if the bleed valve to the bypass settings have been fully restored to the engine's pre-oscillation settings, and a return command 327 to return the program counter
  • FIG. 33 is a flow chart for a novel gas turbine jet engine hybrid anti-icing system 110, 120, 130, 140 for a four engine aircraft.
  • the purpose of this system is to alleviate icing conditions within the compressor section of the jet engine by oscillating and/or dithering the settings to each engine's bleed air valve to the engine bypass, as well as each engine's throttle, to create a hybrid anti-icing oscillation system.
  • This system is comprised of an anti-icing control routine 330 that governs behavior of subroutines that are nested within the program; a power ON or OFF conditional 331 that determines whether the hybrid oscillation anti-icing control routine 330 is set to ON.
  • the routine When the power is OFF or returns with a NO, then the routine reverts back to the anti-icing control routine 330 unchanged.
  • the program proceeds to a hybrid oscillation schedule subroutine 332 to calculate the hybrid oscillation schedule according to the each compressor's temperature and/or pressure gradient; parallel calls 333A and 333B to the Hybrid Oscillation Sub One subroutine, depicted in FIG. 35; and parallel calls 334A and 334B to the Hybrid Oscillation Sub Two subroutine, depicted in FIG. 36.
  • At least one engine control unit 339 with control over at least one engine 50, 60 maintains communication with the anti-icing control routine 330, and the system's other routines 331, 332, 333, 334 during the anti-icing system's 110, 120, 130, 140 operation. Note that the juxtaposition of engines using offsetting bleed settings will only be necessary if constant fuel is maintained during the oscillation of the bleed valve to the bypass. Altering the temperature gradient within the engine will still occur, even at constant thrust, once the bleed valve setting has been altered.
  • FIG. 34 is a flow chart for a novel gas turbine jet engine hybrid anti-icing system for a two engine aircraft.
  • the purpose of this system is to alleviate icing conditions within the compressor section of the jet engine by oscillating and/or dithering the settings to each engine's bleed air valve to the engine bypass, as well as each engine's throttle, to create a hybrid anti-icing oscillation system, while maintaining constant direction by adjusting the plane's rudder.
  • This system is comprised of an anti-icing control routine 340 that governs behavior of subroutines that are nested within the program; a power ON or OFF conditional 341 that determines whether the hybrid oscillation anti-icing control routine 340 is set to ON.
  • the routine When the power is OFF or returns with a NO, then the routine reverts back to the anti-icing control routine 340 unchanged.
  • the program proceeds to a hybrid oscillation schedule subroutine 342 to calculate the hybrid oscillation schedule according to the each compressor's temperature and/or pressure gradients; a parallel call 343 to the to the Hybrid Oscillation Sub One subroutine, depicted in FIG. 35; a parallel call 344 to the Hybrid Oscillation Sub Two subroutine, depicted in FIG. 36; and a parallel yaw adjust routine 345 to compensate for yaw by using the autopilot to adjust the rudder.
  • At least one engine control unit 349 with control over at least one engine 50, 60 maintains communication with the anti-icing control routine 340 and the system's other routines 341, 342, 343, 344, 345 during the anti-icing system's 110, 120, 130, 140 operation.
  • the juxtaposition of engines using offsetting bleed settings will only be necessary if constant fuel is maintained during the oscillation of the bleed valve to the bypass.
  • adjusting for yaw will only be necessary if constant fuel is maintained during the oscillation of the bleed valve to the bypass. Altering the temperature gradient within the engine will still occur, even at constant thrust, once the bleed valve setting has been altered.
  • FIG. 35 is a flow chart for a novel subroutine, referred to as "Hybrid Oscillation One", which is utilized by the anti-icing systems presented in FIG. 33 and FIG. 34.
  • This subroutine is comprised of an initialization routine 350 that stores the engine's operation settings at the outset of the initialization routine 350; a throttle increase routine 351 to gradually increase the throttle according to the compressor stage's temperature and/or pressure gradient; a throttle peak conditional 352 to determine whether the throttle has increased to its target peak setting; a throttle decrease routine 353 to gradually reduce the throttle; a throttle trough setting conditional 354 to determine whether the pressure ratio has been reduced to its initial setting; a bleed valve open routine 355 to gradually open the bleed valve to the bypass according to the compressor stage's temperature and/or pressure gradient; a bleed valve open conditional 356 to determine if the bleed valve open setting target has been reached for the engine; a bleed valve restoration routine 357 to gradually close the bleed valve to the bypass to the same
  • FIG. 36 is a flow chart for a novel subroutine, referred to as "Hybrid Oscillation Sub Two", that is utilized by the engine control modules presented in FIG. 33 and FIG. 34.
  • This subroutine is comprised of an initialization routine 360 that stores the engine's operation settings at the outset of the initialization routine 360; a bleed valve open routine 361 to gradually open the bleed air bypass valve according to the compressor stage's temperature and/or pressure gradient; a bleed valve open conditional 362 to determine whether the bleed valve's target setting and/or compressor's pressure trough target has been reached; a bleed valve close routine 363 to gradually restore the reduced compressor pressure by closing the bleed valve to the bypass; a bleed valve restoration conditional 364 to determine whether the bleed valve settings and/or the compressor's pressure has been fully restored to the subroutine's initial settings; a throttle increase routine 365 to gradually increase the throttle according to the compressor stage's temperature and/or pressure gradient; a throttle peak setting conditional 366
  • the pressure ratio is defined here as the ratio of the inlet pressure of the low pressure compressor and the exit pressure of the high pressure compressor. This can be altered by maintaining constant fuel flow to the engine while simultaneously adjusting the bleed valve to the bypass. Conversely, throttle can be can be maintained by compensating for pressure losses or gains. This would be done by increasing or decreasing the fuel flow respectively in response to changing pressure conditions created by altering the bleed valve setting.
  • FIG. 37 is a diagram representing the temperature changes to the surface temperature of an exit guide vane during a test flight encounter with ice particle meteorological conditions.
  • This exit guide vane surface temperature time series is represented alongside the turbofan's low pressure compressor rotor speed, abbreviated as Nl.
  • the unmodified engine's low pressure rotor speed, Nl, during ice particle meteorological conditions 370 reflects the engine stability resulting from engine modifications (heat applied to the exit guide vanes), whereas the unmodified engine's low pressure rotor speed 371 reflects the deterioration of engine performance during ice particle meteorological conditions.
  • the modified exit guide vane temperature 372 is higher than unmodified exit guides vane temperature 374.
  • Fig. 38 is a flow chart depicting how a switch located in the cockpit, and therefore available to the pilot, may serve as a basis for the pilot to control the operation of the anti- icing system. It is comprised of a cockpit 380, a mechanical, hydraulic, and/or electronic switch 381, an anti-icing oscillation system 382, and an engine control unit 383 with operative control over at least one engine's 384 fuel flow and other operating parameters.
  • the anti-icing oscillation system 382 may communicate indirectly with the engine 384 through the engine control unit 383, or it may communicate directly with the engine 384.
  • variable geometry While the vast majority of commercial turbofan engines do not incorporate variable geometry into their designs, any jet engine that does utilize variable geometry can adapt this invention to include its use. Altering variable geometry in or surrounding the engine, or the engine's angle of attack, will alter the airflow gradient within the engine. Therefore, deliberately oscillating variable geometry is a viable method for oscillating a jet engine's compressor environment gradient.
  • each engine possesses an electrical generator. Because the generator's power is derived from the operation of the engine, oscillating the electrical production of the generator can also be used to oscillate a jet engine's compressor environment gradient. However, given the importance of maintaining electrical power, this method is not emphasized.

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Abstract

La présente invention porte sur un système antigivrage pour un compresseur de turboréacteur à double flux pour surmonter les conditions de givrage qui ont lieu à l'intérieur de l'étage de compresseur central des conceptions actuelles de moteur à réaction à turbine à gaz. Les systèmes antigivrage favorisent généralement l'oscillation des conditions environnementales du compresseur central du moteur, telles que sa température et/ou son gradient de pression. Faire ainsi permet au moteur de perturber le processus de fusion, d'évaporation et de recongélation. Ainsi, l'oscillation de la température et/ou du gradient de pression du moteur empêche le givre de s'accumuler à l'intérieur du compresseur central du turboréacteur à double flux en inhibant la capacité de refroidissement d'évaporation pour un endroit donné. De plus, en déformant la forme de composants du compresseur avant le givrage central, l'oscillation de la manette des gaz fait en sorte que le givre tombe en continu à l'état sous-critique. Enfin, des réglages de manette de gaz interdits et vibrant de façon asymétrique peuvent être utilisés pour empêcher l'accumulation de givre sujette à des gradients de température d'exercer ses effets de refroidissement maximaux.
PCT/US2010/001219 2009-05-12 2010-04-24 Dispositif et procédé de prévention et d'élimination d'accumulation de givre dans un compresseur de moteur à réaction par vibration de la vanne de prélèvement d'air par poussées asymétriques WO2010132086A1 (fr)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013154650A3 (fr) * 2012-01-31 2014-05-22 United Technologies Corporation Ensemble stator d'entrée centrale antigivrage pour turbine à gaz
US11047316B2 (en) 2019-04-09 2021-06-29 Pratt & Whitney Canada Corp. Method of ice removal by inducing sudden variation of rotor speed in a gas turbine engine

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5028017A (en) * 1989-08-08 1991-07-02 Federal Express Corporation Mobile system for deicing aircraft
US6440317B1 (en) * 1996-03-18 2002-08-27 Fuel Dynamics Cyclonic ice separation for low temperature jet fuels
WO2008045065A1 (fr) * 2006-10-12 2008-04-17 United Technologies Corporation Contrôle de l'accumulation de givre sur un moteur d'avion et des composants statiques et rotatifs de nacelle

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5028017A (en) * 1989-08-08 1991-07-02 Federal Express Corporation Mobile system for deicing aircraft
US6440317B1 (en) * 1996-03-18 2002-08-27 Fuel Dynamics Cyclonic ice separation for low temperature jet fuels
WO2008045065A1 (fr) * 2006-10-12 2008-04-17 United Technologies Corporation Contrôle de l'accumulation de givre sur un moteur d'avion et des composants statiques et rotatifs de nacelle

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013154650A3 (fr) * 2012-01-31 2014-05-22 United Technologies Corporation Ensemble stator d'entrée centrale antigivrage pour turbine à gaz
US11047316B2 (en) 2019-04-09 2021-06-29 Pratt & Whitney Canada Corp. Method of ice removal by inducing sudden variation of rotor speed in a gas turbine engine

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